Process of separating slate from coke.



w. s. BLAUVELTKL w. T. HARMS.

PROCESS OF SEPARATING SLATE FROM CdKE.

APPLICATION FILED JULY 8.19M.

1 1 92,1 59. Patented July 1916.

anvemfow WARREN S. BLAU'VELT, OF GROSSE ILE, AND WILLIAM T. HARMS, OFDETROIT, MICHI- GAIN, ASSIGNORS, BY MESN E ASSIGNMENTS, T0 SEMET-SOLVAYCOMPANY, OF SOLVAY, NEW YORK, A CORPORATION OF -NEW YURK.

I TROCESSDF SEPARATING SLATE FROM COKE.

To all whom it may concern.

, Be it known that we, Wanner; S. BLAU- vEL'r'and WILLIA T. HARMS,citizens of the United States, residing, respectively, at Grosse Ile andDetroit, in the county of l/Vayne and State of Michigan, have -inventeda new and Improved Process of Separating Slate from Coke, of whichthefollowing is a specification.

As is well known, in the production of coke from coal as in retort cokeovens, the coal is charged into the oven in a pulverized state. With thecoal is also charged into the oven such slate as may have been presentin the coal and crushed therewith, in

pieces the maximum dimensions of which range from one-sixteenth tothree-eighths of an inch. Such pieces of slate are not changed incharacter by the coking process. While their presence, in the usualproportion, does not injuriously affect the character of the coke as awhole, they do tend to weaken the coke structure at the points wherethey occur so that the coke fractures at these points and the pieces ofslate, which produce the fractures, break off and are mixed andcollected with the small pieces of coke, or breeze, which thus becomesover-' charged with slate. In order to make the coke breeze desirablefor commercial use it is necessary to separate the slate, or someportionof it from the coke. Various means which have been operativelyinefiicient or commercially unsuccessful have been devised and attemptedfor this purpose. Thus, the slate may be removed in the well knownhydraulic process with jigs, but in this case the coke becomes so-saturated with water that in order to make it fit for commercial use itmust be dried at a prohibitive cost. Various attempts to utilize thegreater specific gravity of the slate to effect its separation in thedry state have also been made, as by dropping the material in front ofan air blast. This, however,=h'as proved unsuccessful since a largeproportion of the fiat pieces of slate in falling present their widestsurface to the air current so that they are carried off and depositedwith the coke.

, The success of our process depends upon two observed characteristicsof the pieces of intermixed slate as distinguished from the coke. Firstthat in proportion to volume the pieces of slate are heavier than theSpecification of Letters Patent. Patented J 111 25 1 916. Applicationfiled July 8, 1914. Serial No. 849,849. 7

pieces of coke. Second that the pieces of slate are relatively thin andflat, whereas the In carrying our process into effect we deliver thematerial to be treated, in a dry state, in a thin layer onto a slowlymowing *belthaving a substantially flat, horizontally disposed surfaceso that the material will rest thereon, across which, preferably atright angles to its direction-of motion, is directed an air blast ofsufficient force to move the pieces of coke across and off the belt. Thescales of slate,by reason of lying fiat on the belt, expose theirsmallest surface, z'. 6., their edges, to the blast pressure, so that agreater force is required to move them than the pieces of coke, whichpresent a greater surface. For this reason, and also because ofthegreater specific gravity of the slate, the pieces of slate remain on thebelt and are carried off inthe tailings.

The operation of our invention is illustrated in the accompanyingdrawings, F igure 1 of which shows aside View and Fig. 2 an end view ofa front of apparatus which may be employed in carrying it into effect.

In the drawings, A indicates a substan tially horizontally disposed belttraveling over rollers, B B, and .C, a twyer, or nozzle, by which an airblast is delivered across the belt and substantially at right anglesthereto.

The pieces of coke, 0, c, and of slate, s, s, are, as shown, deliveredonto the belt in a thin layer, as from a hopper, D, so that the piecesof slate, 8, lie upon their sides on the belt. Thus their edges arepresented to the air blast, across which they are carried by themovement of the belt While the' pieces of coke are blown off from theside of the belt the slate is carried along without being disturbed andfinally delivered into a separate receptacle or heap at the end of thebelt. 4

In order to accomplish the best results, we grade the material to betreated so as to deliver it to the belt in pieces of substantiallyuniform size and treat the different grades separately, 6. 9., we maydivide it into two sizes, the larger size comprising those pieces whichwill pass through an opening one-half inch square and over a screenhaving one-fourth inch square openings, and the smaller size those whichwill pass through the. one-fourth inch square openings, and overone-eighth inch square openings. In this manner we avoid the difliculty,encountered if the two sizes are treated together, that an air blast ofa strength'suflicient to blow the pieces of coke of thelarger size offthe 'belt will also take with them the pieces of slate of the smallersize, while a blast of so low a velocity as not to move the smallerpieces of slate will permit the larger pieces of coke to go with theslate into the tailings. By grading the material, however, as abovedescribed, so that only pieces of coke and slate of substantiallythesame size shall be associated and subjected to the air, blast at thesame time, the strength of the air blast can be so regulated as toeffect fine coke which consists in disposing the material to be treatedin a thin layer in a submanner that the edges of the pieces of slateshall be presented to the action of the blast whereby the pieces of cokeare separated from the slate by the action of the blast and the piecesof slate aremoved across and out of the air blast.

2. The process of separating slate from.

by the pieces of. coke are separated. from the slate by the action of'the'blast and the pieces of slate are moved across and out of theblast. I

In testimony whereof we have hereunto subscribed our names this'29th dayof June A. D., 1914. WARREN S.'BLAUVELT.

WILLIAM T. HARMS.

Witnesses: I a

PETER B. KoEBEL,

ROBERT 'E. Hammer.

